Draft Import Risk Analysis - Biosecurity New Zealand

appropriate detection and identification method be identified, a PFA declaration could be
considered an effective phytosanitary measure.
Pest free place of production (PFPP)
Given the paucity of information available on the epidemiology of CRSV on Malus it does not
seem likely that, in the absence of a reliable low cost method for detecting and identifying the
presence of this virus, a reliable PFPP determination could be obtained.
Virus indexing of mother plants
Of the six to eight major viruses of carnations, CRSV is the only one that produces highly
diagnostic and reproducible concentric necrotic ringspots on several diagnostic hosts including
Dianthus barbatus, Gomphrena globosa and Nicotiana clevelandii. Other diagnostic hosts
include Chenopodium amaranticolor, C. quinoa, Tetragonia tetragonioides or Vigna
unguiculata. Inoculation of one of these herbaceous indicators can be followed by one of several
formats of ELISA that have been developed and are effective in identifying CRSV (CPC 2007,
Lommel et al. 1983).
There is currently no information on the reliability of mechanical inoculation of CRSV infected
plants on to susceptible indicator plants, or the sensitivity and specificity of the diagnostic tests.
To reduce the likelihood of false negatives the inoculation test should be repeated again the
following season. The two-test indexing schedule should be considered an effective
phytosanitary measure against CRSV (see section 4.3.1 for more discussion).
Inspection of mother plants
Relying on the detection of CRSV infection without targeted testing would offer little protection
as this organism can remain latent in Malus hosts. Mother plant inspections alone should
therefore not be considered an effective phytosanitary measure against CRSV.
5.2.4. References
Allan H H (1982) Flora of New Zealand. Volume 1. Indigenous Tracheophyta - Psilopsida,
Lycopsida, Filicopsida, Gymnospermae, Dicotyledons. First electronic edition, Landcare
Research, June 2004. Transcr. A. D. Wilton and I. M. L. Andres.
http://FloraSeries.LandcareResearch.co.nz. Accessed 25 March 2009
Brunt A A, Crabtree K, Dallwitz M J, Gibbs A J, Watson L, Zurcher E J (eds.) (1996 onwards).
Plant Viruses Online: Descriptions and Lists from the VIDE Database. Available at:
http://image.fs.uidaho.edu/vide/
CPC (2007) Crop Protection Compendium on Internet. CAB International, Wallingford, UK;
http://www.cabi.org/compendia/CPC/
Dodds J A, Tremaine J H, Ronald W P (1977) Some properties of carnation ringspot virus
single- and double-stranded ribonucleic acid. Virology 83: pgs 322-328.
ICTVdB Management (2006). 00.074.0.04.001. Carnation ringspot virus. In: ICTVdB - The
Universal Virus Database, version 4. Büchen-Osmond, C. (Ed), Columbia University, New
York, USA; http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/00.074.0.04.001.htm
Kegler H, Kegler G, Kleinhempel H (1983) Epidemiological investigations on carnation ringspot
virus and tomato bushy stunt virus in fruit orchards. Zeszyty Problemowe Postepów Nauk
Rolniczych 291: pgs 155-162.
Kleinhempel H, Gruber G, Kegler H (1980) Investigations on carnation ringspot virus in fruit
trees. XI International Symposium on Fruit Tree Virus Diseases. Acta Horticulturae (ISHS)
94: pgs 107-112
DRAFT Import Risk Analysis: Viruses, Viroids, Phytoplasma, Bacteria and Diseases of
Unknown Aetiology on Malus Nursery Stock
August 2009 Page 33 of 203